Leptospirosis is the most common zoonosis yet it is underreported. It is estimated to affect tens of millions annually and if not treated early in the infection can lead to severe complications and can be fatal. Leptospirosis is contracted through skin or mucous membrane contact with urine of infected animals. Most often this occurs by contact with contaminated bodies of water or soil. The World Health Organization lists the groups of people at risk of the infection ranging from cattle and pig farmers to veterinarians, butchers and slaughterhouse workers to children playing in rain puddles or mud, as well as people engaging in recreational activities such as swimming, boating, caving or fishing. In short, there are few people who are not at risk of leptospirosis infection. However, because the initial presentation of the infection is often that of non-specific viral infections, such as influenza, early diagnosis and treatment is infrequent. Thus, there is a critical need for a rapid and accurate point-of-care diagnostic tool for detecting pathogenic Leptospira in patients potentially exposed to urine contaminated soils and bodies of water. To address this challenge, Luna Innovations Incorporated and Rapid Pathogen Screening, Inc. propose to develop immunoaffinity-based Leptospira detection assays using tightly-regulated proteolysis to provide enzymatic signal amplification. The proposed Phase I program will deliver a highly sensitive and easy-to-use rapid diagnostic tool for direct detection of pathogenic Leptospira. A key feature of this platform design is that the signal results from an amplification cascade culminating in complete activation of the enzymes that act upon the signaling molecule. Because the signal is generated by the amplified enzymatic activity, it is conceivable that a single pathogenic particle in the clinical sample would generate the same level of proteolytic activity, and therefore the same robust signal as that generated by a sample containing thousands of the pathogens of interest. Thus, Luna's pathogen-induced signal amplification platform should produce very sensitive as well as rapid point-of-care diagnostic assays. For this Phase I program, Luna will produce and purify and characterize novel assay reagents and demonstrate sensitivity and selectivity of the assay for diagnosis of pathogenic Leptospira. The Phase II program will focus on converting the solution-based assay into the lateral flow format for a user friendly point-of-care assay as well as validating the assay for clinical applications. PUBLIC HEALTH RELEVANCE: Leptospirosis, an infection resulting from skin or mucous membrane contact with urine of infected animals, is considered the most common zoonosis worldwide. It is estimated to affect tens of millions annually with mortality rates ranging from 5 to 25%. Leptospirosis is treatable with antibiotics, however early diagnosis is necessary for antibiotic therapy to be effective. Because the initial presentation of the infection is often that of non-specific viral infections, such as influenza, early diagnosis and treatment is infrequent. Luna Innovations Incorporated and Rapid Pathogen Screening, Inc. (RPS) propose to develop a sensitive and selective point-of- care diagnostic assay for the direct detection of pathogenic Leptospira in clinical samples for deployment in resource-limited regions of the globe.